chore(deps): update dependency @squonk/mui-theme to v4

Author: renovate[bot]

package.json

@@ -54,7 +54,7 @@
     "@sentry/nextjs": "8.37.1",
     "@squonk/account-server-client": "4.0.0-beta.4",
     "@squonk/data-manager-client": "3.1.0-beta.2",
-    "@squonk/mui-theme": "3.0.2",
+    "@squonk/mui-theme": "4.0.0",
     "@squonk/sdf-parser": "1.3.0",
     "@tanstack/match-sorter-utils": "8.19.4",
     "@tanstack/react-query": "5.59.20",